Center punch



July, 10, 1923. mmmz A. FORSYTH I CENTER PUNCH Filed Oct. 27, 1920Ira/6721507? 05% exa7zde7-f57 @/z/ Patented July 10, 1923.

ALEXANDER FORSYTH, OF WESTBORO, MASSACHUSETTS, ASSIGNOR TO ARTHUR M.

, FRASER, 0F WESTBORO, MASSACHUSETTS.

CENTER PUNCH.

Application filed October 27, 1920. Serial No. 420,009.

To all whom it may concern:

Be it known that I, ALEXANDER Fonsyrn, a subject of the King of England,residing at lVestboro, in the county of Worcester and State ofMassachusetts, have invented new and useful Improvements in CenterPunches, of which the following is a specification.

This invention relates to an improvement in center punches and the like.

The object ofthe invention is to provide a tool for making anindentation upon the surface of an object usually constructed of metal,the said indentation being made by said tool without the employment of ahammer or other similar independent striking instrument or withoutnecessitating the em ployment of more than one hand for positioning thetool upon the work and thereafter operating said tool.

The invention consists in the combination and arrangement of parts setforth in the following specification and particularly pointed out in theclaim thereof.

Referring to the drawings:

Figure 1 is an elevation of my improved center punch.

Fig. 2 is an elevation similar to Figure 1 illustrating the method ofoperating the tool.

Fig. 3 is a longitudinal section through the tool.

Like numerals refer to like parts throughout the several views of thedrawings.

In the drawings, 5 represents a tapered member preferably constructed ofhardened steel terminating at its lower end in a point 6 by whichsuitable indentations or marks may be made in the surface of the workdesired, as, for example, the end of a shaft 7 see Figure 2. Detachablysecured at the upper end of the member 5 is a shank 8 which hasscrew-threaded engagement with said member at 9. A shoulder 10 is formedat the junction of the shank 8 and the member 5. A striker 11approximately spherical in form is slidably mounted upon the shank 8,the lower surface thereof abutting against the shoulder 10, being forcedthereagainst by a helical spring 12 which surrounds said shank. Thelower end of the spring 12 abuts against the upper surface of thestriker 11 while the upper end of said spring 12 abuts against the undersurface of a head 13 formed at the upper extremity of the shank 8, thespring being at all times under compression between said head and saidstriker. The upper surface of the head 13 is slightly recessed at 14 inorder that a thumb or finger may rest therein in operat ing the tool Thegeneral operation of the tool is as follows :-With the tool grasped inone hand in any manner suitable to the operator, but preferably with thethumb or forefinger located in the recess 14 as illustrated in Figure 2,the point 6 of the tool is positioned upon the work 7. The striker 11 isthen raised as illustrated in Figure 2 to a suiiicient height to givethe desired amount of compression to the spring 12, after which the saidstriker is released, being forced downwardly by the spring and strikingagainst the shoulder 10. The blow imparted to the shoulder 10 istransmitted through the member 5 to the work and an indentation madetherein by the point 6, the size of the indentation depending upon theforce of the blow and the degree of hardness of the work. If one blow ofthe striker 11 is not suificient to form an indentation of the sizedesired, the blows may be repeated indefinitely until an indentation isformed the size desired.

I claim:

A center punch embodying therein a member provided with a point at itslower extremity and also provided with a shoulder formed thereon, ashank located at the upper extremity of said member and havingscrewthreaded engagement therewith, a head formed integral with saidshank at the upper end thereof and provided with a recess thereinconstituting a finger rest, a striker slidably mounted upon said shankand a spring surrounding said shank between said head and said strikerand adapted to force said striker against said shoulder.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

ALEXANDER FORSYTH.

Witnesses:

J OHN M. Yorme, .Anrnnu M Fnasrn.

